An organic light-emitting display device may include, e.g., a thin film transistor (TFT) and an organic electroluminescent device (EL device), which may be driven by the TFT and may produce an image. The TFT may include, e.g., a gate electrode, an active layer, and source and drain electrodes that are stacked on a substrate. The organic EL device may include, e.g., a pixel electrode, an opposite electrode disposed facing the pixel electrode, and an emission layer interposed between the pixel electrode and the opposite electrode.